Former test driver De Villota, on a tour promoting her autobiography Life Is A Gift, was found in a hotel room in Seville. She was 33.
A spokeswoman for Seville police indicated De Villota's death was via natural causes - with the suspicion she suffered a heart attack - although she added the police could not yet provide confirmation.
Current Williams development driver Wolff, who is from Oban, spoke of the support De Villota had given her before her first serious outing with the team at Silverstone in July.
She said: "Out of the paddock and out of the motorsport bubble, she was an incredible character, she was a fighter. She had such a spirit for life. What she came through was a testament to her strength of character and her positive outlook on life. She was just an incredible lady, no matter what she did on the race track. She was just an incredible character."
The daughter of two-time grand prix starter Emilio, De Villota chose a difficult career path for a woman, but competed in a variety of open-wheel and hard-top categories over the years.
After a test with Lotus Renault in August 2011, De Villota was given her big break in March last year when she was appointed test driver with Marussia.
An ambassadorial role followed in June with the FIA's newly founded Women & Motorsport Commission, but then a month later De Villota was involved in a freak testing accident at Duxford Aerodrome.
It resulted in De Villota losing her right eye, and almost her life, but after a month's recuperation in hospital she eventually made a remarkable recovery.
A Health and Safety Executive spokeswoman said the investigation into last year's accident was ongoing.
McLaren team principal and chairman of the Formula One Teams' Association, Martin Whitmarsh, said: "She was an inspiration, not just to women in this sport, but also to all those who suffered life-threatening injuries."